VPL-VW5000ES. Technical Background VPL-VW5000ES

Transcription

1 Technical Background

2 Key technology #4: High Dynamic Range (HDR) If 4K is about more pixels, then HDR is about better pixels. In audio, dynamic range defines a system s breadth of reproduction from the softest possible sounds (limited by the noise floor) to the loudest (limited by the distortion ceiling). In video, it s the breadth of reproduction from the darkest possible black to the brightest possible highlight. Compared to conventional, Standard Dynamic Range (SDR), HDR delivers home entertainment with unprecedented immersion and impact. Just as anyone who has experienced high definition is spoiled for standard definition, once you ve seen a proper demonstration of HDR, you ll never want to look back. SDR falls short of human vision The human visual system is incredibly versatile. We can perceive light values from 10-6 candelas per square meter (cd/m 2 ) for starlight all the way to 10 8 cd/m 2 for direct sun. That s a ratio of 100,000,000,000,000:1. This is essentially our dynamic contrast ratio. However, simultaneous contrast ratio is another matter. To accommodate the range from starlight to sunlight, the irises in our eyes need to adjust. At any given instant, the human visual system can only accommodate a luminance range of 10 5, Think of this as a simultaneous contrast ratio of 100,000:1. To accommodate such a broad range of light levels, the irises in your eyes need to adjust, a process that takes some time. Like the human eye, television and cinema cameras also have adjustable irises that operators use to accommodate the difference from daytime to nighttime light levels. Like the iris in the human eye, the mechanical iris in the camera s lens adjusts to accommodate the huge variations in light levels from day to night. 15

3 Within a single scene, the human visual system s dynamic range is far more limited, on the order of 100,000:1. Even this narrower range is beyond the reach of conventional television technology. Early television cameras couldn t capture 100,000:1. CRT televisions couldn t display 100,000:1. They were limited to a maximum brightness of just 100 nits (100 cd/m2). Analog TV broadcasting, 8-bit digital recording and 8-bit HDTV broadcasting can t preserve all the nuances of a 100,000:1 image. For all these reasons, conventional, SDR reproduction has been stuck with a dynamic range closer to 1,000:1. SDR television systems can t match the dynamic range of the human visual system. The HDR opportunity Since the 1950s, a suite of technical advances has made the limitations of SDR increasingly obsolete. For the first time, it is now practical to create an end-to-end television system that comes close to reproducing the human visual system s 100,000:1 capabilities. This is High Dynamic Range. The current generation of digital motion picture and TV broadcast cameras can capture HDR. The current generation of professional digital recorders feature 10 bits or more of precision, capable of recording HDR. The very latest professional monitors, such as Sony s BVM-X300, enable directors and cinematographers to evaluate HDR images on- set during the shoot and also during critical postproduction processes such as color grading. New display technologies can deliver HDR to movie theaters, home theaters and televisions. For the first time, HDR can convey this entire 100,000:1 range all the way from the camera set through to the viewer. HDR preserves the 100,000:1 range of human vision. 16

4 HDR benefits HDR benefits almost every type of content, from cinematic drama to TV sports. Nighttime cityscapes are a classic demonstration of HDR. A proper presentation of this effect would require HDR authoring and HDR viewing, conditions that do not apply here. The best we can provide are simulated images that can only give you a rough idea of the true comparison. Greater impact. Compared to HDR, SDR is a pale imitation of life. We ve seen that SDR falls far short of the contrast you experience in real life, while HDR can achieve that contrast. Images become more vibrant, more compelling and more involving. The advantage is most obvious in scenes with dynamic extremes: fireworks, pyrotechnics, sunsets or city skylines lit up against a deep black night sky. You see blacker blacks, higher peak brightness and better tonal gradations in between. More information. With SDR, detail is in constant danger of being lost in the darkest and brightest areas of a scene. Professionals call these losses crushed blacks and clipped highlights. The limitations of SDR force content creators to constantly squash scene dynamic range to fit into the constraints of the narrow SDR distribution pipeline. In scripted productions such as movies and episodic TV shows, the process of color grading often squashes the range to ensure that the SDR distribution master retains important storytelling details in highlights and shadows. But live productions, such as TV sports, don t have that luxury. When the action moves from stadium shadows into bright sunlight, the picture momentarily becomes overexposed. That s because an SDR camera properly exposed for shadows, can t cope with bright sunlight. We can t follow the action until a broadcast technician adjusts the camera s iris. With HDR, no adjustment is necessary. HDR can deliver the entire event from shadows to highlights seamlessly. 17

5 This pair of simulated images illustrates how SDR clips highlight details and crushes black details that HDR retains. In these simulated images of live sports, the SDR broadcast can t accommodate the dynamic range from in bright sunlight to stadium shadow. The HDR broadcast can. 18

6 In these simulated images, the resolution is identical. Only the difference in contrast accounts for the higher perceived sharpness. Greater sharpness. Distinct from resolution, sharpness describes the subjective impression that an image creates. Achieving high sharpness requires both high resolution and high contrast. Because HDR enables a significant boost to reproduced contrast, picture details will pop as never before. Images will be crisper and more lifelike. Sony built the to take advantage of all these benefits. Thanks to the high brightness of 5,000 lumens, high contrast ratio and the ability to accept HDR inputs, the projector is ready. If you supply proper HDR source material and operate the projector in a proper environment, the image is absolutely staggering. The VW5000ES also incorporates operating refinements that make it easy to get the most out of the HDR experience. HDR Auto Mode automatically detects the digital flag that identifies HDR content (as well as the companion BT.2020 color gamut). The projector automatically switches to HDR settings. So you automatically get the correct settings, whether you re watching SDR or HDR. HDR Contrast adjusts contrast level for HDR independently from your SDR setting. You get satisfying on-screen brightness and contrast for all your content. On-Screen Display. To confirm what you re watching, we ve also added HDR indication to the Signal Type field in the Information page of the On-Screen Display. HDR companion technologies Accompanying HDR is a substantial portfolio of image enhancements. In addition to 4K Ultra HD resolution, options available to cinema and television producers include Wide Color Gamut, improved grayscale rendition and High Frame Rate. 19

7 HDR is not about any single specification. It marks a simultaneous improvement in five key aspects of picture quality. These quality improvements work in concert, particularly 4K Ultra HD resolution and HDR. So you re not just getting more color gradations, you re also getting more pixels on which to apply them. HDR and 4K work synergistically to deliver more organic images a picture more like life itself. Wide Color Gamut with BT.2020 emulation Constrained by CRT television phosphors and tube-equipped television cameras, SDTV had a limited range or gamut of possible colors. This means that subjects with the deepest, most saturated green, yellow, orange, red and violet appear muted or muddied. This can degrade the reproduction of both natural colors (flowers) and artificial colors (neon lights) as well as other emissive sources (volcanoes, sunsets). The CIE chromaticity chart is a two dimensional plot that shows every visible hue. In RGB reproduction systems, the gamut forms a triangle defined by the Red, Green and Blue primaries at each corner. Surprisingly, the digital SDTV color system standardized by the International Telecommunication Union, ITU-R BT.601 (called BT.601 or Rec. 601 for short) occupied a CIE chromaticity triangle that covers only about 36% of visible hues. Because CRTs were still the dominant display technology during the development of HDTV, the HD color range was no larger. The HD color gamut defined by ITU-R BT.709 (Rec. 709) was no more extensive than the SDTV gamut. The HDTV color gamut, ITU-R BT.709 color (inner triangle) covers only about 36% of visible colors. The Digital Cinema Initiatives P3 gamut (middle triangle) is larger. Ultra HD ITU-R BT.2020 color dwarfs them both, covering about 76% of visible colors. The development of plasma and OLED flat panel displays plus the availability of LCD displays with a dazzling range of backlight technologies have opened up a new world of color reproduction. On the digital projection side, new light sources and filters have also enabled superior color. It was to overcome previous limitations and to anticipate future improvements in display technology that the ITU specified a far greater range of color for 4K Ultra HD. The Rec standard more than doubles the range of reproducible colors. Compared to SDTV (Rec. 601) and HDTV (Rec. 709), both of which deliver 36% of visible colors, the Rec gamut covers 76% of visible colors. 20

8 Connect a compatible source and you ll see flowers, foliage and other natural colors with newfound realism. You ll notice the difference in the most saturated greens, yellows, oranges and reds. Emissive light sources, particularly fire, lava and neon lights, will appear on-screen as never before. And the CIE chromaticity chart only tells part of the story. It says nothing about reproducing colors across the range from dark to light. To do that, we need to add another dimension, going from color area to color volume. In terms of color volume, the difference between HDTV and 4K Ultra HD is staggering. Because HDR combines wider color gamut with higher peak brightness, you not only get a wider color area. You also get greater color volume with the vertical axis representing peak brightness in nits (cd/m 2 ). This chart compares 100 nit Rec. 709 and 1,000 nit Rec direct view displays, but the concept also applies to the projector. 21

9 Thanks to Sony s TRILUMINOS Display color system, the color gamut extends far beyond BT.709. An Auto Color filter engages to increase the projected gamut. In this way, the projector covers 100% of the Digital Cinema Initiatives P3 color gamut and the overwhelming majority of the BT.2020 color gamut. The projector enhances color with DCI P3 reproduction and BT.2020 Emulation. (Images simulated.) To take full advantage, the projector includes color remapping modes that enhance the color expression of conventional BT.709 sources. DCI P3 reproduction for motion pictures and BT.2020 Emulation for 4K UHD deliver deeper, more saturated color optimized for whatever you re watching. Improved grayscale rendition In theory, we could imagine an HDR video system with one-bit encoding. A digital 1 could represent white, while a digital 0 could represent black. In practice, we need our video pictures to represent grayscale values between peak white and black. And that requires more bits. Conventional HD recording systems, HDTV broadcasting and conventional Blu-ray Disc all represent images with 8-bit digital samples. While careful observers will sometimes see issues, under most circumstances these 8- bit samples are sufficient to represent SDR images. But when you try to squeeze HDR images into an 8-bit pipeline and then stretch HDR back out on the screen, problems appear. Tonal gradations that should appear smooth and continuous become visibly stair-stepped. The problem, called banding or posterization, is bad enough on still images. On moving pictures, it can be extremely distracting. So along with High Dynamic Range, 4K Ultra HD can also deliver higher bit depth, such as 12-bit image capture and distribution. Because major HDR distribution channels are opting for 10-bit, our discussion will focus on that. In these simulated images, insufficient grayscale rendition (left) causes horizontal banding in the sky. This artifact is absent in the image on the right. 22

10 In digital pulse code modulation, each additional bit of accuracy doubles the number of available quantization levels or codelevels available in the three channels: black-and-white luminance (Y), blue color difference (C b ) and red color difference (C r ). While 8-bit video has about 250 codelevels per channel, 10-bit video increases that to about 1000 codelevels. HDR not only increases the number of codelevels, but can also improve their efficiency. SDR video is tied to gamma encoding, a system created to compensate for the characteristics of 1950s era cathode ray tube televisions. HDR can replace gamma with approaches better matched to the needs of the human visual system. These include Perceptual Quantization (PQ) and Hybrid Log Gamma (HLG). The combination of HDR, wide color gamut and 10-bit quantization enables far more accurate rendition of grayscale. If you re not a professional photographer, it may be hard to appreciate how important this is. When photographers and cinematographers light a scene, they re looking for much more than adequate exposure; they re painting with light. Cinematographers use lighting to show the viewer where to look in the frame. Lighting also helps convey emotion, defining moments of terror, intimacy, conflict and peace. SDR tends to oversimplify these subtle gradations, flattening faces and muting the intended emotional impact. For cinematographers, HDR provides a vastly expanded canvas on which to tell stories. For audiences, HDR provides a more immediate, more immersive, more emotionally compelling entertainment experience. The combination of 10-bit grayscale and 4K Ultra HD resolution results in powerful synergies. Expanded grayscale offers a wider range of brightness levels while 4K provides more pixels across which to paint those levels. The combination of 10-bit grayscale and 4K resolution is particularly powerful. On the left is an image that starts with peak white at the left, fading to full black at the right. Consider a horizontal sequence of a few pixels in the middle. Each pixel has brightness recorded as a digital codevalue. The higher the codevalue, the brighter the pixel. With the picture rendered in 8-bit HD (upper left chart), the scarcity of brightness steps equates to a gradation that s somewhat rough. Simply increasing the resolution to 4K (lower left chart) does nothing to improve this gradation. 10-bit HD is somewhat better (upper right). But the smoothest gradation is clearly 10-bit 4K (lower right). 23

11 The is primed to take full advantage of HDR content distribution. The projector has two HDMI 2.0 inputs with a maximum data rate of 18 Gigabits per second. In HDR mode, the projector accommodates signals of 3840x2160 resolution and 10-bit or 12-bit quantization at frame rates of 24p, 25p, 30p, 50p and 60p. High Frame Rates (HFR) For an additional measure of you-are-there realism, High Frame Rates can make a big difference. Almost all movies are shot at the relatively low rate of 24 frames per second (fps). Conventional HDTV offers a choice: maximum resolution or maximum frame rate. For maximum resolution, most US television broadcasting takes place at 1080/60i. Which means you get 60 half-frames (fields) per second, but only 30 complete frames per second. While 1080/60i renders motionless backgrounds in great detail, the frame rate can add blur to moving parts of the image. Other US broadcasters have opted for maximum frame rate, in order to render motion as smoothly as possible. By broadcasting at 720/60p, they deliver 60 complete frames per second, which can be a benefit for TV sports. Introduced in 2015, Sony s Emmy Award winning HDC-4300 became an instant hit with sports broadcasters by combining HFR and 4K Ultra HD together with the ability to accept standard broadcast lenses. With 4K HFR, there s no reason to choose. You can get high resolution and high frame rates at the same time, with 2160/60p. That s eight times the information of either 1080/60i or 720/60p. This is incredible resolution on both still and moving parts of the image. This soccer ball simulates motion blur. Higher frame rates render motion with more intermediate steps. Although shutter speed is a creative choice, higher frame rates are also associated with the faster shutter speeds that minimize motion blur. 24

12 Some Hollywood directors are eager to adopt High Frame Rates in the movie theater while others remain cool to the prospect. Opinions differ at the movies, but there are other entertainment platforms where High Frame Rates are gratefully accepted: videogames and televised sports. HFR videogames represent a major leap forward in immersion and pulse-pounding excitement. Scenes are rendered with heightened detail. And even the most frenetic action appears smooth and sharp. 4K/60p sports are breathtaking. You can survey the entire football field, sideline to sideline and read all the players names. When athletes spring into action, they remain free from motion blur. HDR and creative intent An engineer might imagine that the purpose of home entertainment is to recreate the original scene as accurately as possible. To this way of thinking, HDR, better grayscale rendition, higher frame rates and wider color gamut are all indisputable advantages, slated for use on every occasion. It s important to note that cinematographers and directors don t think like engineers. Depending on the story, moviemakers may deliberately choose to shoot in black-and-white, ignoring color gamut altogether. And while higher frame rates can be more lifelike, lifelike is not always the top priority. Many cinematographers continue to be passionately loyal to 24 fps, a standard that dates to the 1920s. HDR and its associated advances in color gamut, grayscale rendition and frame rate all empower creative artists with a new range of choices. You can think of these advances as new tools in the creative toolkit, new keys on the piano keyboard or even new colors in the artist s palette. While some directors will leap at the opportunity to use these new tools for all they re worth, others may use just one or two. It all depends on creative intent. The HDR entertainment ecosystem Until recently, the entire infrastructure of motion imaging both for the cinema and the home had been built on the basis of Standard Dynamic Range. This means Digital Cinema, HDTV broadcasting, DVD and conventional Blu-ray Disc were all designed around SDR. To get the best out of HDR, you need content that was captured in HDR, color graded in HDR, distributed in HDR and displayed in HDR. The entertainment industry is moving rapidly to make the complete HDR production and distribution chain a reality. HDR cinema. In the movie theater, the Digital Cinema Package (DCP) that studios send into the theater can accommodate HDR. And the first HDR capable projectors are being installed into theaters. Over-the-top HDR streaming. Sensing an opportunity to stake a claim on the frontiers of picture quality, streaming services have been eager to exploit the potential of HDR. Popular services including Netflix, Amazon Prime and Vudu are already producing and distributing highly promoted original series in HDR. 25

13 HDR packaged media: Ultra HD Blu-ray. Standardized in May 2015, Ultra HD Blu-ray embraces Ultra HD (3840 x 2160 resolution), the BT.2020 color gamut, High Frame Rates and HDR with 10-bit grayscale encoding. Sony s UBP-X1000ES and UBP-X800 Ultra HD Blu-ray players are expected to be available spring HDR videogame consoles. Both Sony s PLAYSTATION 4 Pro and the Microsoft Xbox One S consoles support 4K HDR gaming. Every aspect of HDR can benefit game play. Improved sharpness, frame rates, contrast and color gamut all add excitement to white-knuckle experiences. Sony s PLAYSTATION 4 Pro entertainment console supports 4K Ultra HD, HDR and High Frame Rates. Over-the-air HDR broadcasting. In the United States, HDTV broadcasting resulted from a mandate by the Federal Communications Commission. To date, there is no such mandate for either 4K Ultra HDTV or HDR. However, a technical standard for next-generation broadcasting, called ATSC 3.0 is in development and testing. Several candidate HDR technologies are currently being considered. HDR satellite broadcasting. In the US, the satellite TV companies have not announced HDR plans yet. So stay tuned. 26

14 A final word In this document, you ll find charts, diagrams and technical explanations. But you won t find the true benefit of the. You can only experience that benefit sitting comfortably in a suitably darkened room with a well-chosen HDR 4K source and the projector in action. Only then can you appreciate the full significance of Sony s achievement Sony Electronics Inc. All rights reserved. Reproduction in whole or in part without written permission is prohibited. Features and specifications are subject to change without notice. Non-metric weights and measures are approximate. Sony, BrightEra, Motionflow, QUALIA, SXRD, TRILUMINOS, TRIMASTER EL, x.v.color, XDCAM, Z-Phosphor and the Sony logo are trademarks of Sony. PLAYSTATION is a trademark of Sony Computer Entertainment. All other trademarks are property of their respective owners. Version 4.0; March 12,